Method of and machine for making gauges and other articles



Mich 111 192%.; w. E. HOKE METHOD OF AND MACHINE FOR MAKING GAUGES ANDOTHER ARTICLES Illlll ll ,llllilllllll lllfk Filed June 28, 1918 ITILE-1Y5- Watented M m 12% E. HOKE, OF ST. LOUIS,

WILLIAM PANY, OF NEW YORK,

MISSOURI, ASSIGNOR T6 PRATT & WHITNEY COM N. Y., A CORPORATION OF NEWJERSEY.

METHOD OF AND MACHTNE FOR MAKING GAUGES AND OTHER. ARTICLES.

Application filed June 28, 1918. Serial No. 242,482.

concern: 1, WILLIAM Home, a residing at the city of St. Louis and Stateof Missouri, have invented a new and useful Methodof and Machine forMaking Gauges and other Articles, of which the following is aspecification.

This invention relates to a method of and 1 a machine for lapping gaugeblocks or similar articles to produce identical sizes and particularlyto produce plane parallel opposite faces separated from each other by anassigned dimension, the method and machine being in some respectssimilar respectively to the method and machine set forth in my copendingapplication for method of and machine for making gauges and otherarticles, Serial No. 289.591, filed April 12th, 1919, which application,as to a part of its subject matter, is a continuation of this presentapplication. The present invention relates particularly to a method andmachine whereby the sizes or lengths of the blocks are automaticallydetermined by positively limiting the reducing action. In theaccompanying drawing 1 have illustrated several embodiments .of themechanical features of my invention and the preferred way of practicingmy improved method, but it will be understood that the drawing is forillustrative purposes only and is not to be construed as defining orlimiting the invention, the claims appended to 135 this specificationbeing relied upon for that purpose.

Of the drawing Fig. 1 is a view illustrating the method of and machinefor lapping gauge blocks.

Fig. 2 is a plan view illustrating one of the laps, and a part of thedisc or spider for moving the gauge blocks between the laps.

Fi 3 is a side elevation to illustrate the relat1ve positions of thelaps and the disc or spider for performing the lapping operation bymovingthe blocks to be lapped between the lapping surfaces. Fig. 4 is aview showinga form of adjustable limit stop which may Ee sired. J

Fig. 5 is; a view illustrating another form of device for actuating thedisc or spider.

Fig.6 is a view showing a number of the finished blocks in assembledrelation in be usetl when de-' which they may be measured and comparedto determine any error that may exist in the dimensions thereof.

As illustrated the machine includes two laps '1 and 2 of similar sizehaving their adjacent faces 3 and 4 made as nearly fiat as possible. Anumber of similar blocks are placed between the two laps 1 and 2, theseblocks forming a group which may be varied as to arrangement but whichis preferably a circular series as shown. While I do not so limit myselfI have shown in the drawing blocks A-A having opposite fiat faces. Forholding the blocks in proper relationship and for other purposes, aswill be presently explained, there is provided a fiat plate or spider5-preferably having suitable apertures 6 therein adapted to receive therespective blocks. Preferably the apertures 6 are larger than the blocksso as to permit turning or rolling movements between the blocks and thespider.

In order to effect lapping, relative movement is effected between theblocks and the laps, this movement preferably being effected by movingthe blocks and holding the laps against any considerable movement. Thelaps are caused to contact with the blocks with a proper pressure'andwhile I do not so limit myself this pressure is preferably secured byarranging the parts horizontally, as shown. by a suitable support, suchas the legs 7 J and the weight of the top lap is utilized to secure thedesired pressure between the laps and the blocks. The top lap ispreferably supported entirely by the blocks. If greater pressure isdesired, additional weight can obviously be applied to the top lap. Thetop lap is entirely free as concerns vertical movement and it can adjustitself as to parallelism with the lower lap in accordance with thelengths of the blocks.

The movements of the blocks are preferably such that every part of theouter surface of each block engages every part of the working surface ofthe corresponding lap which is engaged by the surface of any otherblock. In this way. all of the blocks are lapped equally. By preferencethe movement is such that each surface of each block engages the entiresurface of the corresponding lap. As illustrated the movement iseffected by bodily moving the spider The lower lap 2 is held preferablyin a circular path. I prefer to make the laps circular in outline and topro- 'vide them with circular central openings, as

shown. Inasmuch as the spider is moved bodily in a circular path itscenter is eccentric of the laps. The degree of eccentricity ispreferably such that the blocks at one side of the spider will projectoutward beyond the outer edges-of the laps, whereas the blocks at theopposite side of the spider will project inward beyond the inner edgesof the laps. Thus the laps are prevented from becoming unevenly worn.Simultaneously with the bodily circular movement the spider ispreferably given a rotative movement, the blocks thus movingcircumferentially around the laps. Preferably the blocks are also givena rotative movement about their own axes in addition to their bodilymovements.

The combined bodily and rotative movement of the spider and blockstogether with the supplemental rotative or rolling movement of theblocksthemselves causes all parts of each block surface to move. past allparts of the corresponding lap surface. At first the laps engage onlythe longer blocks but later, if the lapping proceeds long enough, theblocks are engaged equally and the combined movement affects all of themin the same way, as before stated, and does not tend to reduce some morethan others.

For moving the spider there is preferably provided a central drive shaft8 having a crank 9 .with a crank pin 10 engaging a central aperture ofthe spider. When the crank 8 is rotated the spider is moved bodily in acircular path. Suitable means is providedfor preventing the laps frompartaking of the movements of the spider. As shown, the bottom lap 2 isheld by the legs 7, and the top lap 1 is held by lugs or guides 11formed on the legs 7 and engaging arms 12 on the lap. Preferably thebottom lap 2 is formed with arms 13 similar to the arms 12, there beingthree equally spaced arms on each lap. The supporting legs 7 areconnected with the arms 13 of the lower lap- 2 and the lugsll on thelegs engage the arms 12 on the upper lap 1, the two laps thus being heldagainst relative rotative movement but being free to move vertically andto adjust themselves as to parallelism within reasonable limits. A drillpress may conveniently .be utilized for supporting and. operating theparts described. The legs 7 may be connected with the table of the drillpress, and the shaft 8 may be the spindle of the drill press.

ll preferably leave the spider 5 entirely free as concerns rotative'movement. the aforesaid rotative or precessional movement taking placeautomatically. This rotative movement usually is in the same directionas the bodily movement, as for instance openings.

means? the clockwise direction. Several difierent factors may beinvolved in causing the rotation of the spider. The blocks that areentirely between the laps tend to turn about their axes in thecounter-clockwise direction, rolling along the walls of their respectiveWhen some of the blocks project beyond the-edges of the laps as shownthese blocks may be forced by the pressure of the spider to turn in theclockwise direction. These several turning movements of the 1ndividualblocks affect the spider in ditferent ways and the result. is that it isgiven a *rotative movement about its axis, which movement as beforestated is usually in the clockwise direction. Ordinarily the spidermakes a complete revolution for every five or six revolutions, more orless, of the crank.

Approximately equal temperature throughout all parts of the laps and theblocks is desirable during the operation of lapping, although it is notnecessary to maintain the temperature at any fixed point. In order.

to maintain all of the parts at equal temperature the mechanism may besubmerged in some liquid such, for instance, as water, oil or coal oil.This is preferably accomplished by placing a tub such as 14 in positionso that liquid therein will submerge thelapping mechanism.

For limiting the relative approaching movement of the two laps 1 and 2,I provide suitable stop devices between them. As shown in Fig. 3, eachof the arms 12 and 13 has a bearing surface in the same plane as themain working surface of the corresponding lap. There are stops 15positioned between the arms of each pair. Each stop is a block ofpredetermined length preferably secured to the lower arm 13.

If preferred, screws, 16 as shown in Fig.

4, may be used in lieu of the blocks 15..

shaft 18 journaled eccentrically in a revoluble bushing 19. A rotarymotion is imparted to the shaft in any proper manner and at the sametime a rotary. motion is imparted to the bushing 19. The movement of thegauge blocks when actuated by this form of device is upon a sort ofcircular spiral curve. causing the spider or disc to move around betweenthe laps.

The basic principle on which this invention rests and the discovery ofwhich formed the preliminary steps leading thereto. reduced to itssimplest form, is that if a startbe made with two surface laps and ofequal size.

edea? four pieces of metal. the pieces can be rethem between the twosurface laps to act as limit stops or supports while the fourth ispassed between the two adjacent surfaces of the laps. By changingthemabout, lapping first one and then the other, using the other three assupporting stops all may be reduced to the greatest thickness of thethinnest one and at the same time produce plane parallel surfaces ofidentical dimension' on them all except the thinnest one. This operationpre-supposes that the two surface laps are perfect planes, which is acondition never obtained in practice. If the imperfection of the surfacelap consists of a depression the result will still be to roduceidentical size in all four pieces; but if the imperfect-ion consists ofa raised spot in the surface it will result in lapping the fourth piecethinner than the other three which are being used as supportin stops,

and sets up a never-ending series 0 reduc tions which can never end inidentical size of all four.

If, however, thesame three pieces be used for support stops and anynumber of other pieces be passed between the same parts of the surfaceof the laps, these other pieces will be made of identical size and withplane parallel faces, even though the laps were not perfect planes northe three support stops Assumingthat the stops are of equal size and thelapsperfect planes, all the pieces constituting the work .will be lappedto identical size and with lane parallel faces. The size, however, wi 1be very slightly thinner than the stops on account of the fact that theworkavill continue to lap until no further pressure rests on the workfrom the upper lap, while the stops will continue to bear upper lapwithout being reduced in size, since there is no and the laps.

The result therefore of imperfections in the lapping surfaces, stops,adjustments, etc., is to produce greater or less departure in sizebetween the stops andthe work wit identical size or truth of the work.These are the conditions which exist in this machine and which enable itto produce plane parallel surfaces of identical dimension with highaccuracy.

Similar results can be produced by ing three or more rectangular piecespreviously lapped plane on one side in a row on a surface plate, side byside with their plane sides down, and-lapping their upper surfaces into.a perfect plane; and then tuming each alternate one, end for end, andat the same time transferring them to a corresponding position at theother end of the row, and again lapping theirupper surfaces to a perfectplane, and by repeating this opout affecting the their surfaces.

- axes, and positively the entire weight of the movement between themplaceration several times theymay finally be duced to identical .size byusing three of made of identical size and with plane parallel oppositefaces, with high accuracy.

In accordance with the basic method as outlined, proper blocks 15 areselected or A-A have been reduced to the desiredlength. As alreadystated, any minor imperfections in the stops or in the adjustmentsthereof will not affect the identity of size of the blocks A or theaccuracy of The length of the blocks maydiflt'er very slightly from theassigned length, but the method is nevertheless sufficiently accuratefor most classesof work. When greater precision is desired, use can bemade of the method as set forth in my H aforesaid copending applicationSerial No. 289,591.

As shown in Fig. 6 a number of blocks made at one time may be or stackand compared ard of length. As the blocks are all of the same sizestheir errors are added and the total error can be readily observed. Thismethod of measurement is described in detail in my aforesaid copendingapplication Serial No. 289,591.

What I claim and desire ters Patent is 1. The method of reducing aseries of similar blocks to identical sizes, the method consisting inarranging the several blocks in a group between two opposed flat laps,causing movement between the entire group of blocks and the laps,callsing the blocks to simultaneously turn aboutindividual limiting therelative apof the laps at a preapart notwithstanding to secure byLetproaching movement determined distance continued movement bet-weenthe blocks an the laps.

placed in" a series with a known stand- 2. The method as set forth inclaim 1 characterized by the production of parallel fiat end-faces onthe blocks.

3. The method as set forth in claim 1 characterized by the production ofparallel fiat end faces on the blocks and by the turning of the blocksabout axes perpendicular to the surfaces of the laps.

4-. The method as set characterized by the production flat end faces onthe blocks and by the turning of the blocks about axes perpendicular tothe surfaces of the laps and further characterized by a relative bodilymovement between the entire group of blocks and the laps in a circularpath.

5. The method of reducing a series of similar blocks to identical sizes,which consists in closely arranging tween two opposed flat laps in agroup of which the several blocks-are individually and freely movablewith reference to the forth in claim 1 of parallel the several blocksbelaps, one of said laps being free to relatively adjust itself as toparallelism with the other laps in accordance with the sizes of theblocks, causing such movement between the blocks and the laps that everypart of the 6. The method of reducing a series of similar blocks toidentical sizes, which consists in arranging the several blocks in acircular series between two opposed flat laps, permitting the said lapsto automatically adjust themselves as to parallelism in accordance withthe sizes of the blocks, causing rotative movement between the entireseries of blocks and the laps parallelly with the working surfaces andabout the center of the series, causing the entire series of blocks tomove bodily in a. circular path.

about a center eccentric of the center of the series, and positivelylimiting the relative approaching movement of the laps at apredetermined distance apart notwithstanding continued movement betweenthe blocks and the laps.

7. The method as set forth. in claim 6 characterized by the productionof parallel flat end urfaces on the blocks.

8. The method of reducing a series of similar blocks to identical sizes,which consists in arrangingthe several blocks in a definite groupbetween two opposed flat laps, permitting the laps to adjust themselvesas to parallelism in accordance with the sizes of the blocks, causingmovement between the blocks and the laps to effect lap-ping, positivelylimiting the relative approaching access? ing surfaces, one of the lapsbeing free to relatively adjust itself as to parallelism, with the othera spider positioned between the laps and having openings therein forblocks to be lapped, means for effecting relative bodily movementbetween the spider and the laps, and means supplemental to the blocksfor positively limiting the relative approaching movement of the laps.

claim 10 in which the limiting means comprises three triangular arrangedstops.

12. A lapping machine as set forth in claim 10 in which the limitingmeans comprises three triangularly arranged tops and in which the stopsare independently adjustable.

13. The method of reducing a number of similar blocks to produceparallel flat end faces and identical lengths, which consists in placingthe several blocks with one end face of-each in engagement with afiatisurface plate, placing a flat lap in engagement with the oppositeend faces of the blocks, simultaneously lapping the upper surfaces ofall of the gauge blockstoa perfect plane, interchanging-some of theblocks on the surface plate to symmetrically distribute variations inlength, and repeating the lapping operation.

14;, The'method of reducing a number of similar blocks to produceparallel flat end faces and identical lengths, which consists in placingthe several blocks with one end 11. A lapping machine as set'forth inface of each in engagement with a flat surface plate, placing a flat lapin engagement with the opposite end faces of the blocks,

simultaneously lapping the upper surfaces of all of the gauge blocks toa perfect plane, reversing the blocks end for end and again placing themin engagement with the surface plate, again placing the lap inengagement with the blocks and simultaneously lapping the upper surfacesof all of the gauge blocks to a perfect plane, interchanging some of theblocks on the surface plate to symmetrically distribute variations inlength and repeatingthe lapping operation. wrnnran n. HQKE.

